Method of heating by steam



Nov. 1, 1932. F. RAYMOND 1,386,222

METHOD OF HEATING BY STEAM Filed May 29, 1950 5 Sheets-Sheet l m r N g 1 i 1/ III/11111110 Nov. 1, 1932. F. RAYMOND 1,886,222

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Nov. 1, 1932. F. I. RAYMOND 1,886,222

METHOD OF HEATING BY STEAM Filed May 29, 1930 5 Sheets-Sheet 5 Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE METHOD OF HEATING BY STEAM Application filed May 29, 1930, Serial No. 457,114, and in Canada July 4, 1929.

My invention relates to the method of heating by steam by the use of steam heating systems whether of the so-called steam, vapor, or vacuum, type, in which a plurality of radiators located, as for example in different rooms or parts of a building, are supphed with steam from a system of piping for distributing the steam from a central point, the present application being, as to certain features thereof, a continuation in part of my application for United States Letters Patent,

Serial No. 293,293, filed July 16, 1928.

Heretofore such systems presented great difiiculty of steady operation in mild weather.

The size of the radiators'is regularly calculated by the engineer who designs the system for the building to emit sufiicient heat, when filled with the heating medium, to heat the building to the desired temperature in the coldest weather. Such a radiator will emit heat at practically the same rate when filled with steam at one pound pressure as it will when filled with steam at five pounds pressure. Therefore, the rate of heat delivery 0" cannot be appreciably reduced by a reduction in ressure.

ystems have been used in which the entire system is operated under a high vacuum to reduce the rate of heat delivery from the U radiators, but even at the highest vacuums obtainable in a practical heating system, the

lows:

rate of heat delivery from the radiators is reduced. to only about one-half the rate of heat delivery at maximum pressure yet for the greater part of the heating season less than one-half the maximum rate of heat delivery is required.

One difficulty that has been encountered in the operation, at reduced capacity, of steam 4L, heating systems of the type'operating at pressures above atmospheric pressure, is that, as the pressure in the system became reduced below a certain minimum, a tendency existed to deliver all the steam to a few of the radiators and no steam to the others, as distinguished from heating all of the radiators only partially, whereas, if the pressure was carried above this minimum the radiators would be all completely filled with steam; and this difficulty is also present, but-to a lesser extent, in systems which are equipped to operate under a vacuum.

Other systems of recent origin have been used employing restrictions in the form of orifices in the pipes and at the radiators to '65 cause a more even flow of steam to all the radiators at reduced capacity and thus make possible the partial filling of all the radiators. 7

While these systems are much superior to those unprovided with such restrictions, there exists the same tendency to fill the radiators which are nearest the source of steam supply more quickly thanthose remote therefrom. While the restrictions referred to may be so calculated as to cause all of the radiators to receive substantially-the same amount of steam for any given pressure, when such pressure is reduced this balance is disturbed and thusthe radiators nearest =7 the source of heat supply will receive their quota of steam whereas the other radiators will receive a lesser amount, if any.

One of the objects of my invention to provide a novel method for controlling the supply of steam from a single point through a system otpipes to a plurality of radiators to the end of overcoming to a very large degree the difliculties which havebeen presented by systems as hitherto designed.

Other, more specific objects, are as fol- To provide for the insuring of the delivery of the heating medium to all of theradiators in the systemwhenever the line with which the radiators are connected is opened to the heat upply.

To provide as nearly as possible the same temperature, or'the same relative filling, in

the last radiators of the sy'stema's in the first radiators thereof.

To provide for the insuring'of the delivery of the heating medium to all of the radiators of the system and at the same time produce a reduced rate of heat delivery therefrom.

To provide for the opening of the radiators to the source of-heat supply before the line with which the radiators are connected .becomes cold.

To provide a novel method whereby the pressure in the steam main "wilLnormally oscillate from a higher to a lower pressure instead of being held at a constant pressure.

To provide for the maintaining of the heat-delivering main, as nearly as possible,

delivery of heat simultaneously by a system of radiators fed from a single mam, than is possible under systems of control hitherto use To provide for the more nearly uniform delivery of heat simultaneously by a series of radiators. fed from a single main and in response to requirements for difierent degrees of heat depending upon the outside temperature, than is possible with systems of control as hitherto provided; and other objects as will be manifest from the following description.

Referring to the accompanying drawings:

Figure 1 is a vertical'sectional view showmg a steam heatingapparatus of the standard one-pipe type provided with equipment rendering it suitable for the practicing of my new method. H

Figure 2 is a similar view of a standard vacuum steam heating apparatus provided with equipment rendering it suitable for the I practicing of my new method.

Figure 3 is a similarview of a standard steam heating vacuum apparatus, the radiators of which are supplied with steam from an outside source, the apparatus having equipment rendering it suitable for practicing my new method.

i ure 4 is an enlarged sectional view of an e ectrical switch device for controlling the heat-generating element of the constructions of either Figs. 1 or 2 and operating in response to change of temperature in the system and the action of which is modified by the outside temperature.

Figure 5 is a view like Fig. 4 of the electrical switch device controlling the supplying of steam to the radiators of the apparatus of Fig. 3. Figure 6 is a view in the radiators of a heating system for practicing my'new method, this view showing one form which the apparatus for controlling the delivery of steam to the radiators, responsive to the temperature of one radiator, may take.

Figure 7 is a similar view showing how the temperature-responsive portions of the apparatus may be located on a different type of radiator.

Figure 8 shows a modification of the apelevation of one of paratus above referred to in which the internal temperature of the radiator is utilized to control the supply of heat to the radiators, instead of the exterior surface temperature thereof as in the structure illustrated in Figs. 6 and 7.

Figure 9 is a similar view of a radiator of the so-called fin type showing associated therewith the mechanism operating in response to temperature changes of the radiator, for controlling the supply of heat to the radiator; and

Fig. 10, a broken fragmentary view illustrating a modification of the apparatus shown in Fi 2.

Re erring to the apparatus illustrated in Fig. 1, 10 represents a steam boiler heated by an oil burner represented at 11, the o ration of which is controlled by the means ereinafter described.

The boiler 10 is shown connected with a steam main 12 having branch pipes or risers 13 which lead to a series of radiators represented at 14 and shown as located in diflerent rooms 15 of a building to be heated. The end of the steam main is provided with an air vent 16 operating to permit the esca e therethrough of air but closing against t e escape of steam or water of condensation. steam main 12 terminates in the return line 17 through which the condensate flows back to the boiler 10.

In accordance with this particular construction the control of the burner 11 is effected by the temperature of the last one of the radiators of the system, namely, the one farthest from the boiler, the mechanism shown for this purpose being operative to effect such control y changes of the temperature at the radiator combined with the outside tem erature.

The mec anism shown .for this purpose comprises a compound thermostat 18 (by which is intended the instrument responsive to temperature fluctuations at the radiator modified by the outside temperature) formed of a tiltable mercury tube 19 (Fig. 4) mounted one disk 20 secured to the inner, free, end of-a Bourdon tube 21, the outer end of which is fixed, as represented at 22, to the stationary The Ill

casing 23 of the thermostat, the tube 19 containing'a pair of contacts 24 and 25 adapted to contact with a bod 26 of mercury in the tube when the latter s tilted to the position shown in Fig. 4, the contacts24 and 25 being rature, in the particular construction shown y locating it at the outer surface of the building.

The bulb structures 33 and 34 are connected with the interior of the tube 21 by p pes 35 and 36, respectively, which together with the tube 21 and bulb structures 33 and 34, contain a fluid which'expands and contracts appreciably with changes of tern erature.

The bulb structure 33 wine 1n the particular construction shown, is positioned against the last coil of the last radiator, may be a single bulb preferably of relatlvely great length to be secured in any suitable way, to contact with portions of the radiator surfaces which are variably heated when the radiator is only partially filled with steam, or it may be a bulb or tube which pro e'cts into the radiator as in the construction shown in Fig. 8 wherein such a bulb 1s represented at 33, or it may be, and preferably 15, formed of a plurality of bulbs, as for example as represented at 37 and 38 in Figs. 6, 7 and 9,

connected in series in the pipe 35, the portion of this pipe extending between these bulbs being flexible and adaptingthese bulbs to be positioned in different relative positions, as-

desired, against the radiator.

The control of the oil burner being 1n response to the attainment of a certain degree of temperature at the last radiator, depending on the outside temperature in the particular apparatus shown, the supplying of steam to all of the radiators fed from the main line 12, or at least to the risers to all of the radiators, before the last radiator can be heated sufiiciently to shut off the burner, 1s insured.

In order to illustrate the operation of the apparatus the various cycles of operation of a heating system under the control of the apparatus now being described, will be considered'.

When the control thermostat 18 starts the oil burner into operation, the steam generated thereby is forced into the piping and the radiators, finally reaching the control radiator at the end of the steam main. Steam continues to be supplied to the radiators until this last radiator has been brought to the correct average temperature corresponding to the outside temperature, whereupon the mercury tube 19 of the thermostat 18 becomes tilted into a position to break the circuit at the contacts 24- and 25, whereupon steam ceases to be supplied to the steam main.

During thiscycle of operations the steam main has become completely 'filled with steam, since steam must reach the last radiator before the control thermostat 18 operates, but the amount of steam entering the radiators may be unequal depending on how well the piping is balanced and on the condition of the air valves with which each radiator is equipped in accordance with common practice.

' Upon the condensing of the steam in the control radiator and the dropping of its average temperature below the correct level the thermostat again automatically operates to again start the oil burner to resume the eneration of steam. Meanwhile steam has een condensing in the other radiators at a rate proportionate to the surface thereof in contact with steam, so that the least filled radiator condenses the least steam. Steam has also been condensing in the steam mains but due to the fact that the radiators generally cool off more rapidly than the steam mains, especially when the steam mains are covered, the steam mains will generally be kept full of steam during the period when the radiators are cooling.

As the thermostat 18 starts the burner into operation for the generation of steam for the I second time, with the steam main full of steam, the steam will start to flow into all the radiators almost simultaneously causing approximately equal'amounts of steam to be supplied to each radiator. Thus with the radiators containing the least steam tending to condense less and the bursts of steam pressure at frequent intervals tending to send equal amounts of steam into each radiator, there will be a decided tendency for the steam to equalize in the radiators after a few cycles thereby .producing the same relative degree of partial filling in all the radiators and consequently the same average temperature of the radiators.

This tendencyto equalize will be present even 1n systems which have not been balanced by the insertion of restricting orifices in the branch lines and it will be present in a one pipe steam system as well as in a two pipe steam system. The most perfect distribution will, of course, be found'in a balanced system rather than in an unbalanced system under this control. However, the distribution will often be highly satisfactory under this con-- trol even in an unbalanced system.

Referring now to the apparatus shown in F ig. 2 which is of a standard vacuum steam heating type, 39 represents a steam boiler heated'by an oil burner represented at 40. The boiler 39 is shown connected with a steam main 41 having branch pipes, or risers, 42 which lead to a series of radiators re 1resented at 43 and shown as located in ift'erent rooms of a building to be heated. The end of which opens into the inlet of a pump 50 which operates to return the condensate to the boiler through a pipe 51. Extending upwardlyinto the tank 48 is a pipe 52 connected with the inlet of a suction pump 53, the outlet of which is represented at 54. The rotors of the pumps and 53 are mounted on a shaft 55 shown as driven by a motor 56.

The operation of the motor 40 is controlled in the same manner as the motor 11 ofthe apparatus of Fig. 1, the contact-making thermostat, corresponding with the thermostat 18 of Fig. 1, being represented at 57 and the bulb elements, corresponding with the elements 33 and 34 represented at 58 and 59, respectively.

In this apparatus the operation of the suction pump 53 causes vacuum to be produced in the steam main 41, the return pipe 45 and the radiators 43, thereby causing steam to enter the steam-main 41 and the radiators at a lower temperature than in the case of the apparatus as shown in Fig. 1 which requires raising the temperature of the water to sub-- stantially 212 F. before steam 1s generated for passage into the steam main and the radiators.

The rovision of the thermostat 57, controlled y. change-"of the temperature of the last radiator of the system, modified by the outside temperature y reason of the provision of the bulb element 59, causes this apparatus to function to supply substantially the same amount of heat to each radiator as explained in the case of the construction shown in Fig. 1. I

The apparatus of Fig. 3 is the same as that shown in Fig. 2 except that, instead of providing a heat-generating element (the boiler 39), the operation of which is controlled by the compound thermostat, steam is supplled to the steam main with which the radiators are connected through a pipe leading from anoutside source of steam supply and provision is made for controlling the supplying ample back to the source of steam supply. A

vacuum pump 68, connected at its inlet with a pipe 69 opening into the upper portion of the tank serves to create the desired degree of vacuum in the system. As in the construction shown in Fig. 2 the pumps 67 and 68 are driven by a single motor (0.

The pipe leading from the outside source of steam supply is represented at 71 and connects with the pipe 60 through a valve 72 the stem 73 of which is pivotally connected at 74 with the lever 75 pivoted at one end, as represented at 76, to the lower end of a link 77 pivoted, at 78, to the casing of the valve 72 and at its other end, as represented at 79, to the upper end of a link 80 the lower end of which is connected with a crank 81 of any suitable mechanism for opening and closing the valve 72 responsive to the temperature at the control radiator modified, in the particular arrangement shown, by the outside temperature.

In the arrangement shown, the mechanism just referred to and represented at 82 is the same as that commonly provided ,for thermostatically actuating the dampers of a coalburning furnace and therefore need not be described in detail the three electric terminals as commonly provided on the mechanism being represented at 83, 84 and 85.

The thermostatic device for controlling the actuation of the mechanism 82 which is operated in response to changes in temperature of the control radiator, modified by the outside temperature, is represented at 86. This thermostat comprises a tiltable mercury tube 87 mounted on a disk 88 connected with the free end of a spiral Bourdon tube 89,'the

by the mercury and when tilted in clockwise direction in this figure, the mercury bridges the contacts 94 and 95. The contact 92 is connected by a wire 96 with the terminal of the mechanism 82; the contacts 93 and 94 are connected, by wires 97 and 98 to a single wire 99 which connects'with the main line wire 100. The other main line wire 101 connects with the terminal 84 and the contact connects, by a wire 102, with the terminal 83. When the tube 87 is tilted to engage the mercury 96 with the contacts 94 and 95, current is supplied to the mechanism 82 for rotating the crank 81 throughout 180 thereby moving the valve 72 to closed position, and upon reverwly tilting the tube 87 to the position shown in Fig. 5 the mechanism'82 is actuated to return the crank 81 to the position shown in Fig. 3 for opening the valve 72.

The condition of the Bourdon tube 89 is controlled by the pressure existing therein governed by the temperature at the control radiator, modified by the outside temperature, through the medium of the bulb elements 103 and 104. corresponding with the bulb elements and 34, respectively, of Fig. l in the ame manner as in the case of the thermostat means of Figs. 1 and 2.

While I have shown in each of the three types of apparatus illustrated in Figs. 1,

2 and the controlling of the heat supply by means which operate in response to changes of the temperature in, or at, the last radiator of a plurality thereot, I do not wish to be understood as intending to so limit it, as any equivalent method of control producing either equally accurate control as is effected by the control from the last radiator or an approach to accurate control may be employed within my invent-ion.

Thus, by way of examples, the temperature in, or at, any portion of the heating apparatus, at a point remote from the source of steam supply, as for example the boiler, may be utilized as the control for the mechanism controlling the supplying of heat, the effectiveness of the control to produce substantially equal heat transmission at each radiator, depending upon how closely such modification of apparatus approaches in its ctiiciency of operation, the operation of a system in which the control is effected by the temperature of the last radiator of a plurality thereof.

A measure of successful operation could be obtained by controlling the steam supply of the radiators at some point in the system immediately adjacent the last radiator, namely, by way of example in a two-pipe steam system, the temperature of the return line leading from the last radiator could be used with advantage as illustrated in Fig. 10 which shows apparatus identical with that shown in Fig. 2 except that the bulb element 58, instead of being positioned against the radiator 43, is positioned against the return line 46 leading therefrom. In certain instances the utilizing of the temperature of the branch line leading to the last radiator for control of the heating medium would result in the successful control of the apparatus.

The control of the heat supplying means by the temperature of a radiator other than the last one of a plurality thereof may be provided for with advantage over controls as hitherto provided especially if a restriction is introduced into one of the branch lines leading to such radiator. Furthermore, a radiator connected to the heat supply by a line individual to it with such a restriction that the flow of steam would flow into it sub While I have illustrated and described apparatuses each of which involves as an element thereof the control of the supplying of heat in response to changes in the temperature of the apparatus produced by the heating medium and modified by the outside temperature, it will be understood that any other desirable means for controlling the temperature of the system to govern the degree of heat transi'nission by the radiators for different outside temperatures may be employed. Thus any desirable mechanism adjustable manually for outdoor temperatures may be provided; and if desired. the operation of the heat-supplying means to be made responsive to the attainment of any desired temperature in or at the control radiator, within certain limits, by the heat-responsive element, or elements, adapted for adjustment into different positions relative to the zones of differential heating of the control radiator, as for ex ample by the adjusting of the single bulb element at the radiator into dilferent positions therein or into diflerent angular positions, or the relativeadjustment of the tandem-disposed relatively adjustable bulbs.

YVhat I claim as new, and desire to secure by Letters Patent, is:

1. The method of regulating the supply of steam to a steam heating system comprising a plurality of radiators connected in parallel to a common source of steam, which comprises controlling the supply of steam to the system in accordance with temperature changes of the system at a point remote from said source.

2. The method of regulating the supply of steam to a system comprising a plurality of radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam to the system in accordance with temperature changes of the system at a point remote from where the steam enters the system and varying the temperature at which said control is effected to vary the supply of steam to the radiators.

3. The method of regulating the supply of steam to a system comprising a plurality of radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam from a source to the system in accordance with the average of the temperature of the outside atmosphere and the temperature ofthe apparatus produced by the heating medium at a point remote from said source.

4. The method of regulating the supply of steam to a system comprising a plurality of radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam to the system in accordance with temperature changes of one of said radiators.

5. The method'of regulating the supply of steam to a system comprising a plurality of radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam in the system in accordance with temperature changes of one of said rasteam to a system comprising a plurality 0 diators and varying the temperature at which said control is effected to vary the supply of steam to the radiators;

6. The method of regulating the supply of steam toia system comprising a plurality of radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam to the system in accordance with the average of the temperature of the outside atmosphere and the temperature of one of said radiators.

7. The method of regulating the supply of 1 radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam to the system in accordance with an average of the outside temperature and the temperature of one of the radiators of the system most remote from the source.

9. The method of regulating the supply of steam to a system comprising a plurality of radiators connected in parallel to a source of steam supply which comprises controlling the supply of steam to the system in accordance with temperature changes of the one of said radiators to which the steam has the greatest length of travel from the point where it enters the system.

10. The method of regulating the sup 1y of steam to'a system comprising a plurality ofradiators connected in parallel to a source of steam supply which comprises controlling the supply of steam to the system in accordance with the average of the temperature of the outside atmosphere and the tem erature of the one of said radiators to which t e steam has the greatest length of travel from the point where it enters the system.

um to a system'of radiators from a source of supply, interrupting the supply of medium when a portion of the system remote from the source of supply reaches a predetermined temperature and substantially equalizing the f amount of the medium in each of the radiators fv by intermittent introduction of medium to 'thesyst-em in accordance with variations in temperature at such remote point.

- FRED I. RAYMOND- 11. The method of vapor heating which I comprises supplying vaporized heating medium from a source to a system of radiators to at least partially fill a plurality of said radiators with vaporized heating medium and maintaining substantially proportional amounts of said medium in each of the said radiators by controlling the supply thereof to the system in accordance with the amount of heating medium present in a portion of the system remote from the source.

12. The method of vapor heating which com rises supplying vaporized heating medium rom a source to a system of radiators to at least partially fill a plurality of said radiators with vaporized heating medium and maintaining substantially proportional 

